Chemical Kinetics and texture interpretation of rocks at high pressures and temperatures

高压高温下岩石的化学动力学和结构解释

基本信息

批准号：
60420016
负责人：
MORI Takeshi
金额：
$ 13.12万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1987
项目状态：
已结题

项目摘要

We have made researches on chemical kinetics of subsolidus reactions among rock-forming minerals at high pressures and temperatures, of both synthetic and natural rocks. As natural rock samples, the Horoman peridotites and basic metamorphic xenoliths at Kibi Plateau were chosen.The most important outcome of the analysis of garnet lherzolites synthesized at high pressures using a piston-cylinder type high pressure apparatus is the experimental demonstration of differential velocities among various subsolidus chemical reactions in the garnet lherzolite mineralogy. That is, the Ca-Mg-Fe redistribuion ,that is rathe simple reaction, took place everywhere in the minerals while such an Al-related reaction as the Tschermak substitution failed at the core. This phenomena, probably due to the relative complexity of reaction mechanisms, would be directly related to the differential closure temperatures among various geothermometers.The analysis of texture and mineral chemistry of natural rocks , in conjunction with the experimental study, led us to deeper understandings in the textures and formation histories of natural rocks. For example, we could decipher that the Horoman peridotites once belonged to the garnet lherzolite facies though the peridotites now totally lack traces of garnet lherzolite facies mineralogy.Future studies : The high pressure apparatus in our laboratory can maintain pressure in lengthy period. On this benefit, we paln to make as lengthy runs as possible so that subsolidus chemical kinetics can be further understood.

我们对合成岩石和天然岩石在高压和高温下的造岩矿物之间的亚固相线反应的化学动力学进行了研究。选择吉备高原的霍罗曼橄榄岩和基性变质捕虏体作为天然岩石样品。使用活塞缸式高压装置对高压合成石榴石二辉橄榄岩进行分析的最重要成果是实验证明了不同介质之间的速度差。石榴石二辉橄榄石矿物学中的固相线下化学反应。也就是说，Ca-Mg-Fe重新分布，即相当简单的反应，在矿物中到处发生，而诸如Tschermak取代之类的与Al相关的反应在核心失败。这种现象可能是由于反应机制相对复杂，与各种地温计的闭合温度差异有直接关系。对天然岩石的结构和矿物化学的分析，结合实验研究，使我们对这一现象有了更深入的认识。天然岩石的纹理和形成历史。例如，我们可以破译Horoman橄榄岩曾经属于石榴石二辉橄榄岩相，尽管现在橄榄岩完全缺乏石榴石二辉橄榄岩相矿物学的痕迹。未来的研究：我们实验室的高压装置可以长时间保持压力。考虑到这一点，我们计划进行尽可能长的运行，以便进一步了解亚固相线化学动力学。